I've seen shafts with the motors attached that you can buy for the terrova. I believe the heads are the same regardless of size of terrova. If I had a 36v and wanted a 24v system, wouldn't I be able to just pull the entire shaft and swap it with a shaft that has a 24v motor?

The reason that I am asking is, I put on a 36v but it is more than I need for my boat and I'd rather have that extra battery to run other electronics. Mounting the entire unit was a pain because I had no access underneath. I was wondering if I could just find someone with a 24v that wanted to upgrade and do it this way to make it simpler on me?

Not at all. The spot lock accuracy isn't suppose to be as good if it is over powered because it will over correct sometimes. I was in it the other night and when the boat decided to correct itself to the left, it hit 10 (max) on the speed and because it swung the bow sideways, italmost threw me off the boat and of course it then over corrected and had to come back around. Not to mention freeing up the space and weight of the extra battery. Some of the Terrova features, you don't have speed control over and too much power can be dangerous.

Not at all. The spot lock accuracy isn't suppose to be as good if it is over powered because it will over correct sometimes. I was in it the other night and when the boat decided to correct itself to the left, it hit 10 (max) on the speed and because it swung the bow sideways, italmost threw me off the boat and of course it then over corrected and had to come back around. Not to mention freeing up the space and weight of the extra battery. Some of the Terrova features, you don't have speed control over and too much power can be dangerous.

My 22' CC Fiberglass bay boat has the 80 lb version it will do the same thing when it decides to turn at 10.

If yours was a saltwater model I would offer a trade, I need a little more power on mine.

Not at all. The spot lock accuracy isn't suppose to be as good if it is over powered because it will over correct sometimes. I was in it the other night and when the boat decided to correct itself to the left, it hit 10 (max) on the speed and because it swung the bow sideways, italmost threw me off the boat and of course it then over corrected and had to come back around. Not to mention freeing up the space and weight of the extra battery. Some of the Terrova features, you don't have speed control over and too much power can be dangerous.

They all do that, I have a 80lb on my 18' boat and it waits way too long to activate/respond. Then it wants to kill you getting back to its spot. This is why guys have gone to the Xi5 instead.